What Is The Delta Variant?
The Delta variant of COVID-19 or the B1.617.2 highly transmissible variant of concern (VOC). The World Health Organisation has categorised it as a VOC because there has been a significantly increased transmissibility. A growing number of countries are reporting outbreaks associated with this variant [1].
The Delta variant has spread to more than 60 countries and is now dominant in the UK. And as per the current reports, Delta is now closing in to overtake Alpha (the first VOC detected in England).
The first case of the Delta variant in India was discovered in the state of Maharashtra. The first mutant virus detected in Kent, UK, is now called Alpha, whereas the South African and Brazillian Variant is known as Beta and Gamma, respectively.
When speaking about the possibilities of the Delta variant mutating further, experts have said that in the case of this variant, high levels of transmission combined with a partially vaccinated population increases the risk of more people catching the virus and raises the risk of further meaningful mutations that could drive Delta further to evade vaccine-induced immunity [2][3].
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What Is A Variant Of Concern (VOC)?
A mutation is declared a VOC when a variant for which there is evidence of an increase in transmissibility, more severe disease which requires increased hospitalisation or causes deaths, a significant reduction in neutralisation by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.
Variants of concern might require one or more public health actions, such as notification to WHO, reporting to CDC, local or regional efforts to control spread, increased testing, or research to determine the effectiveness of vaccines and treatments against the variant.
Also, depending on the characteristics of the variant, additional considerations may include the development of new diagnostics or the modification of vaccines or treatments.
What Are The Specific Symptoms Of The Delta Variant?
According to the reports from India, the symptoms of the Delta variant are as follows [4]:
- Stomach pain
- Nausea
- Vomiting
- Loss of appetite
- Hearing loss
- Joint pain
- Hearing loss
- Severe gastric problems
There have been cases where people have developed microthrombi, or small blood clots, so severe that they led affected tissue to die and develop gangrene, where some required amputations of fingers or a foot [5].
The aforementioned symptoms, according to reports, were not reported in COVID patients infected with the Beta and Gamma variants.
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Why Is The Delta Variant A Variant Of Concern?
Although there is no solid proof currently, health experts believe that the recent surge in the number of COVID-19 cases in the second wave could be attributed to the Delta variant [6]. This variant is a cause for concern because as the delta variant carries the genetic code from two other mutations, E484Q and L452R, it becomes easier for it to break into the human immune system and invade the organs.
Also, as the new variants tend to alter the structure of the spike protein, it is more efficient in attaching itself to the human host cells and multiplies swiftly, doing more damage than a COVID strain without any mutation [7].
That is, there are two primary reasons which make the Delta variant a VOC, and they are:
- It has about a 40 per cent higher transmission rate compared with Alpha, which already had a 50 per cent higher transmissibility than the original strain of the virus.
- It is believed to cause more severe disease than the Alpha variant, causing a further rise in the percentage of positive cases that require hospitalisation, despite the fact that the infections are in younger people.
- According to a study by researchers from the National Institute of Virology in Pune, the Indian Council of Medical Research and vaccine manufacturer Bharat Biotech which has not yet been peer-reviewed, Bharat Biotech’s Covaxin is effective against the Beta and Delta variants of Covid-19 [9].
- Another pre-print study asserted that the Serum Institute of India’s Covishield vaccine produced more antibodies than Covaxin; it was conducted by Coronavirus Vaccine-induced Antibody Titre and involved healthcare workers who have received both doses of either Covaxin or Covishield [10].
- A preliminary study conducted by the All-India Institute of Medical Science (AIIMS) Delhi claimed that the presence of COVID-19 Delta variant (B1.617.2) is predominantly found even after getting a single dose or both doses of COVID-19 vaccine [11]. Read More
Doctors across the globe are concerned that that the Delta variant could be the reason behind increased hospitalised patients. Added to that is the multiple cases of blood clot formation in the chest of the severe COVID patients without any past history of coagulation-related problems. There are also reports that doctors have identified clots in the blood vessels linked to the intestines, resulting in severe stomach pain [8].
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Does The Delta Variant Respond To Vaccines?
Scientists had pointed out that there are chances that the vaccines may not be very effective against the new mutated variants. Some studies on the effectiveness of vaccination on the Delta variants are as follows:
Which Countries Have Reported The Delta Variant?
As of now, the Delta variant has been reported in over 60 countries. In the United Kingdom, the Delta variant has led to more hospitalisation in COVID patients than before.
According to the data collected from GISAID, a global science initiative and primary source established in 2008 that provides open access to genomic data of influenza viruses and the coronavirus responsible for the COVID-19 pandemic, the U.K. has the highest proportion of the delta variant outside of India, at 70 per cent of its cases. The U.S. is showing about 5 per cent (and growing), and Germany is at about 2 per cent. Italy and Spain are each at about 3 to 5 per cent [12].
On A Final Note…
Initially, the Delta variant was named the Indian variant because WHO had earlier said that viruses or variants should not be identified by the names of countries they were found in. However, India had objected to the variant being labelled as the Indian variant.
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